Presentation Information
[S08-02]Fracture energy of earthquakes scales linearly with slip across ten orders of magnitude
*Sae Watanabe1, Kazuki Masuda1, Yoshihiro Kaneko1 (1. Graduate School of Science, Kyoto University)
Understanding earthquake rupture growth processes and the resulting seismic radiation is essential for advancing earthquake source physics and mitigating seismic hazards. While scaling laws of source parameters provide critical insights into the physical processes driving rupture, existing physics-based models cannot fully explain these scaling relations. This study tests the hypothesis that spontaneous dynamic rupture models, incorporating hierarchical patches of fracture energy within a linear and non-linear slip-weakening friction framework, can reproduce several well-established scaling laws. Earthquakes ranging from magnitude M=-12 (laboratory events) to M=6 (large crustal events) are simulated to quantify source parameter scaling laws, including seismic moment, source duration, magnitude-frequency distributions, moment growth, fracture energy, stress drop, and scaled energy. Our results show that regardless of input friction parameters or slip-weakening friction frameworks, modeled stress drops and scaled energy remain constant across magnitudes, and other source scaling laws derived from the simulations are consistent with observational inferences. However, modeled fracture energy scales linearly with mean slip, contradicting previous observational studies suggesting a quadratic or nonlinear dependence with mean slip. Sensitivity analysis reveals that input friction and stress parameters do not significantly affect this trend. By reassessing observational data, we identify biases in previous fracture energy and mean slip estimates. Applying model-based corrections, we find that fracture energy scales linearly with mean slip across 10 orders of magnitude. These findings have important implications for understanding the energy budget of small and large earthquakes and the mechanisms governing rupture growth on natural faults.